This invention relates generally to deposition technologies and, more particularly, to a technology for controlling the depth of deposition of a solvent free functional material in a receiver.
In a typical ink jet recording or printing system, ink droplets are ejected from a nozzle towards a receiver (recording medium, recording element, etc.) to produce an image on the receiver. The ink droplets, or recording liquid, generally comprise a marking material or functional material, such as a dye or pigment or polymer, and a large amount of solvent. The solvent, or carrier liquid, typically is made up of water, an organic material such as a monohydric alcohol, a polyhydric alcohol, or mixtures thereof. The liquid ink droplets are ejected from the nozzle using pressure pulses generated by an oscillating piezoelectric crystal or by heating the nozzle to generate an ink droplet resulting from bubble formation or from ink phase change. Alternatively, the liquid ink droplets can be ejected in a continuous manner with selected ink droplets being allowed to impinge on a receiver while other ink droplets are collected in a gutter.
A receiver typically comprises a support having on at least one surface thereof an ink-receiving or image-forming layer. In order to achieve high quality, high resolution images on the receiver, the receiver should be readily wetted so there is no coalescence of adjacent ink dots (commonly referred to as puddling) which can lead to non-uniform ink droplet density. The receiver should also exhibit no image bleeding; exhibit the ability to absorb high concentrations of ink droplets and dry quickly to avoid elements blocking together when stacked against subsequent prints or other surfaces; and exhibit no discontinuities or defects due to interactions between the support and/or layer(s) (e.g cracking, repellencies, comb lines, etc.). Additionally, the receiver should not allow unabsorbed dyes to aggregate at the free surface of the receiver causing dye crystallization, which results in bloom or bronzing effects in the imaged areas.
The requirements listed above are all affected by the ability of the receiver to manage the solvent fluid volume efficiently and in a manner as to prevent image degradation arising from persistent solvent effects. Such fluid management issues, in turn, place strong demands on the receiver, requiring complex receiver designs and correspondingly complex and expensive manufacturing options.
Referring to FIGS. 7A and 7B, a conventional inkjet print using conventional inkjet inks and a conventional inkjet printer imaged on conventional photographic inkjet paper is shown The receiver 14 includes a paper base 92 coated with two ink receiving layers, a base layer 94, and a top layer 96. Ink 98 (a mixture dye and solvent) is retained in the top layer 96 by a mordant. However, the solvent diffuses into the receiver 14 carrying with it the dye which causes bleeding of the ink 98 into the base layer 94. This makes the accurate deposition of dye or another functional material in the receiver 14 very difficult.
The requirements listed above become less critical in situations where the ink solvent diffuses through or away from the receiver element at time-scales many orders of magnitude higher than that of the dyes or pigments. This can be achieved by dispersing the dye particles in a highly volatile liquid medium, for example, highly volatile organic solvents such as acetone, or in a gaseous medium, such as an aerosol. However, volatile organic solvents, like the ones described above, are not preferred because of safety and health issues that accompany the use of these solvents. Typically, these solvents are highly flammable and are also known carcinogens. As such, appropriate safety measures are needed when they are used which increases associated costs and severely limits their usefulness.
Technologies that deposit a marking material such as a toner particle onto a receiver using gaseous propellants are known. For example, Peeters et al., in U.S. Pat. No. 6,116,718, disclose a print head for use in a marking apparatus in which a propellant gas is passed through a channel, the functional material is introduced controllably into the propellant stream to form a ballistic aerosol for propelling non-colloidal, solid or semi-solid particulate or a liquid, toward a receiver with sufficient kinetic energy to fuse the marking material to the receiver. There is a problem with this technology in that the functional material and propellant stream are two different entities and the propellant is used to impart kinetic energy to the functional material. This can cause functional material agglomeration leading to nozzle obstruction and poor control over functional material deposition. Another problem with this technology is that when the functional material is added into the propellant stream in the channel it forms a non-colloidal ballistic aerosol prior to exiting the print head. This non-colloidal ballistic aerosol, which is a combination of the functional material and the propellant, is not thermodynamically stable. As such, the functional material is prone to settling in the propellant stream which, in turn, can cause functional material agglomeration leading to nozzle obstruction and poor control over functional material deposition.
As such, there is a need for a technology that permits high speed, accurate, and precise deposition of a solvent free functional material on a receiver. Additionally, there is a need for a technology capable of controlled functional material deposition within a receiver or within a predetermined layer of a receiver. There is also a need for a technology that permits functional material deposition of ultra-small (nano-scale) particles. There is also a need for a technology that permits high speed, accurate, and precise patterning of a receiver that can be used to create a high resolution patterns on a receiver.
There is also a need to develop suitable receivers that, when used in conjunction with the technology described above, assist in the accurate deposition of the functional material without being adversely impacted by the functional material. There is also a need to develop suitable receivers that permit the accurate positioning of the functional material on the receiver or within the receiver (e.g. within a predetermined layer of the receiver, a predetermined distance from the receiver surface, etc.). Additionally, there is a need to develop receivers that meet other requirements critical for broad consumer acceptance (e.g. receiver properties such as basis weight, caliper, stiffness, smoothness, gloss, whiteness, opacity, etc.) in addition to being suitable for use with the technology described above.
An object of the present invention is to provide a technology that permits high speed, accurate, and precise deposition of a solvent free functional material on a receiver.
Another object of the present invention is to provide a technology capable of controlled functional material deposition within a receiver or within a predetermined layer of a receiver.
Another object of the present invention is to provide a technology that permits high speed, accurate, and precise patterning of a receiver that can be used to create a high resolution patterns on a receiver.
Another object of the present invention is to provide receivers that assist in the accurate deposition of the functional material without being adversely impacted by the functional material.
Another object of the present invention is to provide receivers that permit the accurate positioning of the functional material on the receiver or within the receiver.
According to a feature of the present invention, a method of delivering a functional material to a receiver includes in order, providing a mixture of a fluid having a solvent and a functional material; causing the functional material to become free of the solvent, and causing the functional material to contact a receiver.
According to another feature of the present invention, an apparatus for delivering a functional material to a receiver includes a pressurized source of solvent in a thermodynamically stable mixture with a functional material, the solvent being in a liquid state within the pressurized source. A discharge device having an inlet and an outlet, the discharge device being connected to the pressurized source at the inlet, the thermodynamically stable mixture being ejected from the outlet, the solvent being in a gaseous state at a location beyond the outlet of the discharge device. A media conveyance mechanism positioned a predetermined distance from the outlet of the discharge device.
According to another feature of the present invention, a method of delivering a functional material to a receiver includes providing a source of a thermodynamically stable mixture of a solvent in a liquid state and a functional material; providing a discharge device having a nozzle in fluid communication with the source of the thermodynamically stable mixture; positioning a receiver at a predetermined distance from the nozzle, ejecting the thermodynamically stable mixture from the nozzle, the solvent changing from the liquid state to a gaseous state; and depositing the solvent free functional material on the receiver.